The present invention relates to a frictional electrostatic voltage measuring equipment for measuring the frictional electrostatic voltage characteristics and the discharge characteristics of a sheet-form sample of textile such as cloth, knitted goods and non-woven fabric, and of a sample such as paper, leather and resin film.
Recently, there has been a rapidly increased demand for a static-control type fiber capable of inhibiting the electrification due to friction and the like and used for applications, for example, the static-control clothes used for semiconductor manufacturing process and the carpets treated so as to protect human body from receiving electrostatic shock. In a situation where many companies have developed various raw materials in response to gradually more sophisticated demand for static control properties, there has been also an increased needs for equipment for evaluating static control properties.
Although equipment for measuring frictional electrostatic voltage characteristics in accordance with the JIS L 1094 have been commercially available, they are insufficient with respect to accuracy and repeatability. Therefore, to develop equipment capable of accurately and simply measuring electrostatic properties has been regarded as extremely important.
As a method for improving the accuracy and repeatability in measuring electrostatic voltage, the following methods have been proposed.
The method disclosed in Japanese Pat. published No. 38656/1987 is a method with which the electrostatic voltage of a sheet-form sample is measured by rubbing the sample with mechanical reciprocating motion or rotating motion using a brush with bristles.
The method disclosed in Japanese Pat. published No. 11303/1987 is a method with which a sheet-form sample with its back supported by a supporting object is urged on its front with a rubbing object to effect rubbing and then allowed to move to the side of a detector along straight line or curve so that the electrostatic voltage of the sample may be measured. The supporting of the sample from its back when rubbed allows the accuracy and repeatability of measurement to be improved.
The method disclosed in Japanese Pat. laid open No. 267658/1987 is a method with which the electrostatic voltage of a sample is measured with a detector facing the sample by moving a supporting object to separate from the sample after or simultaneously with the end of rubbing. The separation of the supporting object from the sample allows the effect on measurement due to the electrification of the supporting object to be eliminated, and the measuring accuracy to be improved.
The method disclosed in Japanese Pat. laid open No. 287148/1987 is a method in which a textile sample with its back supported by a supporting object is rubbed on its surface by a rubbing object, moved while adhering to said supporting object simultaneously with or after the end of rubbing, faced to an electrostatic detector, separated from the said supporting object simultaneously with or after the completion of movement, and measured for electrostatic voltage by the electrostatic detector facing the sample.
In these methods, all samples are supported by a supporting object. However, some problems still remain unsolved in that attaching and detaching of a sample to and from the supporting object is difficult to perform, and sequential measurement of many samples requires much labor.